How To Increase Calcium Absorption

Consumers need to be aware that there are other factors that affect calcium absorption, and the effectiveness of calcium, irrespective of the type of supplement they choose.

Vitamin D

Vitamin D is very important in allowing the body to absorb calcium from the intestines. It does this through its' effect on the proteins required to transport the calcium across the membrane of the intestines and into the blood stream.

Vitamin D also helps maintain the optimal balance of calcium and phosphorus in the bone mineralization process. 

Vitamin C

Vitamin C also helps with calcium supplement absorption. You can often find calcium supplements with vitamin C added.

Magnesium

Magnesium contributes to the bone matrix, like calcium. It also works with calcium in regulating heart and muscle contraction, and other functions involving the blood, nerves, and muscles. Thus, it's important to make sure you're getting enough magnesium in your diet for your calcium supplements to be truly effective. A good ratio to aim for is 2:1, although you should watch the tolerable upper limits for magnesium if you're taking more than 1000mg of calcium a day. You may exceed the recommended amount of magnesium if you follow the 2:1 ratio in this instance. 

Lactose

Lactose, found in dairy products, helps with the calcium absorption in the intestines in infants, although there is no evidence it really helps adults absorb more calcium.

Dietary Considerations

Diet plays a variable role in calcium supplement absorption. Often, it's a case of getting the right balance of a food. For example, fat and protein in our diets help the absorption of calcium, but only if these are not eaten in excess. A diet that is high in fact or protein will actually reduce overall calcium absorption. With protein, this is done by increasing the rate at which calcium is excreted in the intestines.

Protein is still an important factor in calcium absorption, particularly the amino acids lysine and glycine. You'll often see calcium supplements in a chelated form (not necessarily with those two amino acids. Chelated supplements are where they are bound to amino acids which help transport the mineral into our bloodstream so the body can use it.

Foods That Inhibit Calcium Absorption

There are some foods you should really watch eating when you take a calcium supplement. Giving your body a two hour window between taking the supplement and eating them is a good rule of thumb.

Foods to watch out for include those high in oxalic acid, such as spinach, rhubarb, chard, chocolate, cocoa, star fruit, parsley, poppy seeds, amaranth, beets, most nuts and berries, and beans.

Tea leaves are also high in oxalic acid, though fortunately for tea drinkers, the beverage itself doesn't have much in it because not a lot of tea leaves are used in the process.

Phytic acid is another plant chemical that inhibits calcium absorption. Phytic acid is found in the hulls of grains, seeds, and nuts. It is the main way that plants store the mineral phosphorus.

There are ways that foods rich in phytic acid can have the levels reduced when we cook and prepare food. Cooking itself reduces phytic acid, as does soaking the foods in an acidic medium such as lemon juice, or fermenting or sprouting foods.

As an example, bread, made from grains, is actually fine because when yeast is added to leaven the dough, enzymes, break down the phytic acid. It's important to note that phytates are not actually bad, they just inhibit the absorption of calcium. It's a question of context.

Caffeine

If you're a moderate coffee drinker, and you get enough calcium in your diet, then caffeine has very little effect on calcium absorption.  Whilst it does reduce absorption a little bit, if you have a tablespoon or two of milk, that offsets any loss.

Stomach Acidity

This is one factor that really shows it pays to research things well on the internet! Many seemingly good sources indicated that having a low stomach acidity was a problem in efficient calcium absorbtion. Yet when I looked further, I found a couple of interesting pages that showed that this was not true.

One discussed the results of studies into the effect of taking calcium when the subjects had taken a stomach acid blocker. They found there was absolutely no effect, and this was true whether the calcium came from milk or supplements. There was even a person who had a medical condition where they had no stomach acid, and they were also still able to absorb calcium.

There is quite an interesting discussion there, so if you're concerned about stomach acidity and calcium absorption, I recommend reading it. 

There is another study here. Of course, these studies were measuring results within the short term. I don't know of any studies done over the long term, although they may exist.

The Amount Of Calcium Taken At Once

Our bodies can only absorb a certain amount of calcium at a time. If you're taking a supplement, divide your calcium supplement into doses of around 500mg. 

Medications

Some medications can reduce the calcium absorption. These include the tetracycline antibiotics, antacids with aluminum in them, diuretics,, and some others.

Aging

We are at our most efficient at calcium absorption when we are younger. As babies and children,. we absorb 50% to 70% of the calcium we take into our bodies. Yet by the time we are adults, this has dropped to 30% to 50%. That's why it's so important we improve our calcium absorption.